5.15-stable review patch. If anyone has any objections, please let me know.
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From: Luis Henriques (SUSE) luis.henriques@linux.dev
[ Upstream commit 907c3fe532253a6ef4eb9c4d67efb71fab58c706 ]
When doing fast_commit replay an infinite loop may occur due to an uninitialized extent_status struct. ext4_ext_determine_insert_hole() does not detect the replay and calls ext4_es_find_extent_range(), which will return immediately without initializing the 'es' variable.
Because 'es' contains garbage, an integer overflow may happen causing an infinite loop in this function, easily reproducible using fstest generic/039.
This commit fixes this issue by unconditionally initializing the structure in function ext4_es_find_extent_range().
Thanks to Zhang Yi, for figuring out the real problem!
Fixes: 8016e29f4362 ("ext4: fast commit recovery path") Signed-off-by: Luis Henriques (SUSE) luis.henriques@linux.dev Reviewed-by: Zhang Yi yi.zhang@huawei.com Link: https://patch.msgid.link/20240515082857.32730-1-luis.henriques@linux.dev Signed-off-by: Theodore Ts'o tytso@mit.edu Signed-off-by: Sasha Levin sashal@kernel.org --- fs/ext4/extents_status.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/fs/ext4/extents_status.c b/fs/ext4/extents_status.c index cccbdfd49a86b..ee52dd6afe543 100644 --- a/fs/ext4/extents_status.c +++ b/fs/ext4/extents_status.c @@ -312,6 +312,8 @@ void ext4_es_find_extent_range(struct inode *inode, ext4_lblk_t lblk, ext4_lblk_t end, struct extent_status *es) { + es->es_lblk = es->es_len = es->es_pblk = 0; + if (EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY) return;